Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 150908
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
508 AM EDT Fri Mar 15 2024

.KEY MESSAGES...

- Dry weather and above normal temps expected today.
- A system brings light rain/snow mix and blustery conditions
  tonight into Saturday.
- Below-normal temperatures, continued blustery conditions into
  early next week and accumulating lake effect snow potential
  Saturday night into Monday night.
- Prolonged gale event on Lake Superior starting tonight and
  lasting into Sunday night.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 506 AM EDT Fri Mar 15 2024

Upper air pattern consists of primarily zonal flow over the UP with
weak ridging over the eastern CONUS and a deep cut off low over the
desert SW, per RAP analysis. GOES Night Fog has shown a few pockets
of low stratus development, with occasional ceiling heights of 300
feet or less having been reported at a few UP ASOS/AWOS sites this
early morning. Virtually no models, including CAMs, have handled
this well, providing a bit of a nowcasting challenge. Have
introduced some patchy fog into the morning forecast to cover for
this, but given poor model guidance, uncertainty is too high to
include anything beyond patchy coverage. In areas where low
stratus has not developed, notably southern Baraga County and
the northern portions of Keweenaw County, lows have fallen below
20 degrees, though much of the rest of the UP will likely
remain in the low to mid 20s for morning lows.

Today, low clouds will hang around but late in the afternoon, high
clouds begin to build in from the west and northwest ahead of an
energetic shortwave which will be over northern MN by 00Z Sat. No
precipitation is forecast by any CAMs prior to 00Z, but growing warm
advection and building SWerly flow will allow daytime highs to climb
to near 50 in spite of any lingering low clouds. Areas of the
interior west that see breaks in cloud cover today may find RHs
falling towards 30%, though wind gusts of only around 10-15 mph
should keep fire weather concerns low.

&&

.LONG TERM /TONIGHT THROUGH THURSDAY/...
Issued at 420 AM EDT Fri Mar 15 2024

Upper air pattern consists of a rex block on the west coast with a
high in the Pacific NW and a closed 500 mb low over the desert sw
00z Sat. There is also a shortwave near Lake Winnipeg which will dig
southeast into the upper Great Lakes 12z Sat which will help to
broaden a trough across the Great Lakes region 12z Sun into 12z Mon.
850-700 mb q-vector convergence moves in 00z Sat along with deeper
moisture and then moves out 12z Sat before returning with a weak
shortwave again for 12z Sun through 12z Mon. Pcpn starts later this
evening as dry southwest winds keep the lower layers dry. Could be a
potential tonight for strong winds in the Keweenaw briefly and
looked at wind advisory potential, but winds gusts get up briefly
about an hour to almost 45 mph at CMX, but problem is it is a
southwest wind. Southwest winds generally are not that gusty at the
airport, so held off on advisory and will mention in mqt product
for now. LES really does not get going until Sat night as well and
then looks to be a prolonged event.

In the extended, the GFS and ECMWF show a 500 mb rex block in the
western U.S. with a high in the Pacific NW and the closed low in the
desert sw 12z Mon and a deep trough across the eastern half of the
U.S. Pattern changes little 12z Tue with the trough broadening over
the east half of the U.S. The rex block breaks down by 12z Wed in
the western U.S. with the ridge becoming weaker and the trough
starting to eject out of the desert sw. This trough then moves into
the southern Rockies 12z Thu and into the lower Mississippi Valley
12z Fri. Upper flow over the upper Great Lakes this forecast period
goes from NW to SE at the beginning to a zonal west to east flow by
12z Fri. Temperatures stay at or below normal for this forecast
period.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 123 AM EDT Fri Mar 15 2024

With satellite imagery showing unexpected low clouds developing over
portions of western Upper MI recently, fcst will reflect ocnl bkn
IFR cigs at IWD and bkn LIFR cigs at CMX for the next couple of hrs.
Meanwhile, at SAW, low MVFR cigs have developed as a stream of low-
level moisture from ne of the lake has spread into n central Upper
MI. These lower clouds should linger for the next several hrs with
VFR thereafter. VFR will then prevail at all terminals today into
this evening. On the backside of a passing sfc high pres ridge
overnight and this morning, guidance does suggest that an area of
stratocu in the 3500-5000ft range will spread across w and central
Upper MI this morning into aftn. Winds at IWD/CMX will become gusty
to around 20-25kt this aftn as pres gradient tightens btwn the
departing ridge and low pres dropping se toward northern Ontario. As
near sfc layer then stabilizes somewhat this evening, LLWS should
develop at IWD this evening. LLWS will be possible at CMX/SAW near
the end or just beyond this fcst period. As aforementioned low pres
system moves across northern Ontario tonight, brief shra will be
possible across western Upper MI late this evening, but potential is
too low to include mention at IWD/CMX attm.

&&

.MARINE...
Issued at 420 AM EDT Fri Mar 15 2024

Winds quickly increase today to 30 knots by late afternoon out of
the southwest. Then a prolonged gale warning event sets up starting
tonight with southwest gales to 45 knots possible with the strongest
winds between Isle Royale and the Keweenaw. The wind becomes
westerly late tonight and northwest on Saturday. As colder and more
unstable conditions move in behind the clipper on Saturday, gales to
35 knots can be expected.

Winds come down below gales late Sun night into Monday as a high
pressure ridge begins to build in from the west. Unstable conditions
remain into the early part of next week, but winds should diminish
to 20 kts or less for Tuesday and Wednesday as high pressure and
warmer conditions move over the area.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning from 8 PM EDT /7 PM CDT/ this evening to 8 AM EDT
     /7 AM CDT/ Sunday for LSZ162.

  Gale Warning from 8 PM EDT /7 PM CDT/ this evening to 2 AM EDT
     /1 AM CDT/ Monday for LSZ240>244-263-264.

  Small Craft Advisory from 2 PM this afternoon to 8 PM EDT this
     evening for LSZ243-244.

  Small Craft Advisory from 2 AM to 8 AM EDT Saturday for
     LSZ245>251.

  Gale Warning from 8 AM Saturday to 2 AM EDT Monday for
     LSZ245>251-265>267.

Lake Michigan...
None.

&&

$$

SHORT TERM...GS
LONG TERM...07
AVIATION...Rolfson
MARINE...07


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